Abrasion-resistant composite-coated string for sports racquets and fishing equipment

ABSTRACT

A string for various kinds of recreational equipment is a composite-coated monofilament string which includes a single filament or a bundle of multiple filaments of string and a composite coating surrounding and bonded to the single filament or bundle of multiple filaments. The monofilament and multifilament string can be made from any of suitable conventional material. The composite coating in each construction of the string includes a matrix material and particles of PTFE interspersed within the matrix material and within a range of about 11% to 20% by weight of the composite coating. The matrix material can be a suitable synthetic material.

[0001] This utility patent application claims the benefit of provisionalapplication No. 60/187,956 filed Mar. 9, 2000.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention generally relates to strings useful insports and recreational equipment and, more particularly, is concernedwith an abrasion-resistant composite-coated string for sports racquetsand fishing equipment.

[0004] 2. Description of the Prior Art

[0005] Strings used in recreational equipment, such as sports racquetsand fishing equipment, are generally constructed of natural materialsand synthetic materials that are well-known in the art. These stringsare sometimes coated with materials intended to protect the structuralelements of the string.

[0006] Typical coatings which have been used to protect the structuralelements of the string include nylon, polyurethane andpolytetrafluoroethylene (PTFE). Nylon and polyurethane are typicallyapplied to the surface of strings by coextrusion of the nylon andpolyurethane onto the surface of the string construction to provide anabrasion barrier to protect the construction of the string. PTFE hasbeen used in the past by dipping the string into a liquid solvent orcarrier containing dissolved PTFE. After dipping the string, the solventevaporates leaving a coating of PTFE. For instance, U.S. Pat. No.4,377,620 to Alexander discloses applying a coating film on the stringby drying a liquid formed by dispersing minute particles of ethylenetetrafluoride resin either in a solvent or a molten resin. The ethylenetetrafluroide resin particles have a diameter from 0.1 to 10 micronsand, in the mixture with a polyester or polyamide resin, are from 3 to10% by weight. The thickness of the coating film is typically in therange of 5 to 40 microns (0.005 to 0.040 mm).

[0007] However, the PTFE does not bond well with the surface of thestring construction and is quickly removed by rubbing the surface of thecoating. While the aforementioned coatings provide some protection, theyare worn away relatively quickly due to abrasion caused by stringsrubbing against themselves or other objects. Therefore, there is a needto improve the abrasion resistance of the coatings used on strings forsports racquets and fishing equipment.

SUMMARY OF THE INVENTION

[0008] The present invention provides an abrasion-resistantcomposite-coated string designed to satisfy the aforementioned need. Thecomposite coating is a matrix material interspersed with PTFE of between11% to 20% by weight. The advantage of the composite coating applied onthe string is that its matrix material provides an acceptable bond tothe respective surfaces of the single filament or bundle of multiplefilaments while the interspersed PTFE reduces the friction resultingfrom adjacent strings rubbing against each other or other objects andtherefore reduces the abrasion and wear on the string.

[0009] Accordingly, the present invention is directed to anabrasion-resistant string for use with various types of recreationalequipment. The string includes a single filament or a bundle of multiplefilaments of string and a composite coating surrounding and bonded tothe single filament or bundle of filaments. The monofilament andmultifilament strings can be made from any of conventional material. Thecomposite coating in each construction of the string includes a matrixmaterial and particles of PTFE interspersed within the matrix material.The matrix material can be a suitable synthetic material, such as nylonor polyurethane.

[0010] These and other features and advantages of the present inventionwill become apparent to those skilled in the art upon a reading of thefollowing detailed description when taken in conjunction with thedrawings wherein there is shown and described an illustrative embodimentof the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In the following detailed description, reference will be made tothe attached drawings in which:

[0012]FIG. 1is a cross-sectional view of a prior art monofilament stringused in sports racquets and fishing equipment.

[0013]FIG. 2 is a cross-sectional view of a prior art coatedmonofilament string used in sports racquets and fishing equipment.

[0014]FIG. 3 is a cross-sectional view of a prior art coatedmultifilament string used in sports racquets and fishing equipment.

[0015]FIG. 4 is a cross-sectional view of an abrasion-resistantcomposite-coated monofilament string of the present invention.

[0016]FIG. 5 is a cross-sectional view of an abrasion-resistantcomposite-coated multifilament string of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0017] Referring to the drawings and particularly to FIGS. 1 to 3, thereare illustrated cross-sections of several different constructions ofprior art strings 10, 12,14 which are all useful in various kinds ofrecreational equipment, mainly, sports racquets and fishing equipment.With respect to the first construction shown in FIG. 1, the prior artstring 10 is a non-coated monofilament string which is only a singlefilament 16 of string. With respect to the second construction shown inFIG. 2, the prior art string 12 is a coated monofilament string whichincludes a single filament 18 and a coating 20 surrounding the singlefilament 18. With respect to the third construction shown in FIG. 3, theprior art string 14 is a coated multifilament string which includes abundle 22 of multiple filaments and a coating 24 surrounding the bundle22 of multiple filaments. The monofilament and multifilament strings andthe coatings can be made from any of the conventional materialsmentioned previously above.

[0018] Referring now to FIGS. 4 and 5, there are illustratedcross-sections of strings 26, 28 constituting two differentconstructions of the present invention which are both useful in thevarious kinds of recreational equipment, mainly, sports racquets andfishing equipment. With respect to the first construction of the presentinvention shown in FIG. 4, the string 26 is a composite-coatedmonofilament string which includes a single filament 30 of string and acomposite coating 32 surrounding and bonded to the single filament 30.With respect to the second construction of the present invention shownin FIG. 5, the string 28 is a composite-coated monofilament string whichincludes a bundle 34 of multiple filaments and the composite coating 32surrounding and bonded to the bundle 34 of multiple filaments. Themonofilament and multifilament strings can be made from any of theconventional materials mentioned previously above.

[0019] The composite coating 32 in each construction of the string 26,28includes a matrix material 36 and particles 38 of PTFE interspersedwithin the matrix material 36. The matrix material 36 can be a suitablesynthetic material such as nylon or polyurethane. The amount of PTFEpartides 38 contained in the matrix material 36 is within the range offrom about 11% to 50% by weight and, preferably, about 20% by weight.The diameter of the PTFE particles 38 in the composite coating 32 isabout 3 to 30 microns (3E-06 meters to 30E-06 meters) and preferably 10microns. The composite coating 32 has a range of thickness about 0.030to 0.050 mm.

[0020] The advantage of this composite coating 32 is that the matrixmaterial 36 provides an acceptable bond to the respective surfaces ofthe single filament 30 and the bundle 34 of multiple filaments of thetwo constructions while the interspersed PTFE particles 38 reduce thefriction resulting from adjacent strings rubbing against each other orother objects and therefore reduces the abrasion and wear on the string.

[0021] It is thought that the present invention and its advantages willbe understood from the foregoing description and it will be apparentthat various changes may be made thereto without departing from thespirit and scope of the invention or sacrificing all of its materialadvantages, the form hereinbefore described being merely preferred orexemplary embodiment thereof.

I claim:
 1. An abrasion-resistant string useful in a sports racquet andfishing equipment, comprising: (a) an elongated single filament ofstring; and (b) a composite coating surrounding and bonded to saidsingle filament of string, said composite coating including a matrixmaterial and particles of PTFE interspersed within the matrix materialand falling in a range of from 11 % to 50% by weight of the compositecoating.
 2. The string as recited in claim 1 , wherein said matrixmaterial is a synthetic material.
 3. The string as recited in claim 1 ,wherein said matrix material is nylon.
 4. The string as recited in claim1 , wherein said matrix material is polyurethane.
 5. The string asrecited in claim 1 , wherein said PTFE particles interspersed in saidmatrix material is about 20% by weight of the composite coating.
 6. Thestring as recited in claim 1 , wherein a diameter of said PTFE particlesin said composite coating is about 3 to 30 microns.
 7. The sting asrecited in claim 1 , wherein said composite coating has a range ofthickness about 0.030 to 0.050 mm.
 8. An abrasion-resistant stringuseful in a sports racquet and fishing equipment, comprising: (a) anelongated bundle of multiple filaments of string; and (b) a compositecoating surrounding and bonded to said bundle of multiple filaments ofstring, said composite coating including a matrix material and particlesof PTFE interspersed within the matrix material and falling in a rangeof from 11% to 50% by weight of the composite coating.
 9. The string asrecited in claim 8 , wherein said matrix material is a syntheticmaterial.
 10. The string as recited in claim 8 , wherein said matrixmaterial is nylon.
 11. The string as recited in claim 8 , wherein saidmatrix material is polyurethane.
 12. The string as recited in claim 8 ,wherein said PTFE particles interspersed in said matrix material isabout 20% by weight of the composite coating.
 13. The string as recitedin claim 8 , wherein a diameter of said PTFE particles in said compositecoating is about 3 to 30 microns.
 14. The sting as recited in claim 8 ,wherein said composite coating has a range of thickness about 0.030 to0.050 mm.